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Translation of abstract (English)

To evaluate differences in total haemoglobin mass (tHb mass) and in red blood cell profile between elite endurance-trained (END, n = 29) and non-endurance-trained (nEND, n = 30) male and female adolescent athletes, tHb mass and specific variables of red blood cell profile ([Hb], Hkt, MCV, MCH, MCHC) were determined in 59 elite junior athletes. It is hypothesized that at the age of 15-17 years, regular endurance training might induce a significant increase in tHb mass and changes in red blood cell profile. Therefore, all parameters were again determined at three time-points separated by 6-month intervals in a subset of 27 of the 59 junior athletes (END, n = 17; nEND, n = 10). In END, tHb mass related to body weight (relative tHb) was ~15% greater than in nEND (11.2 ± 1.6 g kg-1 vs. 9.7 ± 1.3 g kg-1, P < 0.001), whereas no significant differences were observed for the red blood cell profile. tHb mass only increased in END, however, relative tHb mass and the variables of red blood cell profile had not changed significantly in both groups in course of 18 months. In conclusion, in elite junior athletes, differences in tHb mass between END and nEND were similar, however, smaller compared with previously in adult athletes reported values. At the age of 15-17 years, 18 months of regular training did not induce significant changes in tHb mass beyond alterations explained by physical growth and also variables of red blood cell profile did not change significantly. The assessment of tHb mass is discussed as a parameter for anti-doping screenings. Determination of tHb mass with the optimized CO-rebreathing method (oCOR-method) requires repeated measurements of the carboxyhemoglobin fraction (%HbCO) using spectrophotometers. In various publications, different spectrophotometers were used. In a side issue it should be determined, whether %HbCO measurements with different spectrophotometers (RapidLab, OSM3) yield similar tHb masses and similar longitudinal tHb mass alterations (D-tHb). Therefore, tHb mass was assessed from simultaneous %HbCO measurements with two different spectrophotometers for a second and a third time (in 37 and 33 of the 57 athletes, respectively) after 6 and 12 months. Because of significant differences in %HbCO measurements between the spectrophotometers, the decisively difference for tHb mass calculations between %HbCO after the CO-rebreathing and the initial values was significantly different as well (RapidLab, 4.7 ± 0.4% vs. OSM3, 4.5 ± 0.5%, P < 0.001). The tHb masses calculated from the OSM3 were 4.4 ± 5.7% higher than the tHb masses derived from measurements using the RapidLab (701.7 ± 150.2 g vs. 671.6 ± 138.7 g, P < 0.001). The correlation of D-tHb masses as determined with the two spectrophotometers over two time intervals was weak (r: 0.28 - 0.57). In only about 66% of all D-tHb mass estimations did D-tHb massOSM3 and D-tHb massRapidLab show the same direction of change. Apparently, the analytical variation in tHb mass determination with oCOR increases considerably with the use of different spectrophotometers. Therefore, agreement on the use of one spectrophotometer that accurately measures low %HbCO values is needed if oCOR should be used in antidoping settings.